The present invention relates to a device to safely feed electricity to low-voltage utilisation apparatuses and it is particularly used in housing and especially in the field of low-voltage lamps.
It is known that in the field of lighting, the use of low-voltage (12-24 volt) lamps is increasing such lamps make it possible to save a great amount of energy. However the use of these lamps, which are still being developed, involves some difficulties due to the necessity of adapting the same to the ordinary-voltage (220 volt) supply mains. Obviously said solution brings about some drawbacks as the cost of the transformers (one for each lamp) greatly affects the cost of the whole lighting unit. In order to avoid each low-voltagelamp needing to be coupled to a transformer, present manufacturers have tended towards feeding devices which, being connected to the ordinary-voltage supply mains by a single transformer, are capable of feeding a plurality of low-voltage lamps.
To this end electrical lines consisting essentially of a support section member to be applied to a ceiling have already been accomplished, the section members being externally provided, on two opposite faces thereof, with two wires extending over the whole length of the rail. In order to allow the lamps to be connected to the electrical lines, suitable adaptors are provided which are engageable with the lines in a removable manner and which exhibit connecting members adapted to connect the wires of the lines to utilisation units such as lamps and the like.
Although the lines show good qualities as to their practical use and operation, they have however some drawbacks. One of them is due to the fact that wires arranged outside can represent a great danger, should mistakes be made in the electric connections at the moment of setting up the line.
In order to eliminate those drawbacks the availability of electrical lines of the above type in which wires are disposed inside the section member as usually happens when rails used for ordinary-voltage (220 volt) supply mains are concerned, would be desirable.
At this point it is also necessary that the adaptors connecting the electrical lines to the utilisation units do not, for the sake of safety, allow the operating interchangeability between low-voltage adaptors and ordinary-voltage adaptors.
The technical problem to be solved is therefore to provide low-voltage rails structured in such a way that the respective adaptors cannot be wrongly connected to ordinary-voltage rails and vice versa.